The universal software of finite element method was developed for solving water diffusion equations of axisymmetrical body. Using the program, a series of numerical solutions were obtained for the 3-layer sphere models and 3-layer ellipsoid models, which were used to describe short and long grain rice respectively. Those results show that the difference of kernels desorption rates between the two models become small when drying temperature is high. The distribution of moisture and its gradients in both models during drying was given for different drying procedures. It was suggested that the boundary condition is better modified to incorporate the phenomenon that surface moisture is changing gradually. Moisture gradient in the kernel varies during drying, and the changing of the gradients may cause damage to the kernels.